Complexity:
The MMSE scheme has a complexity of \(\mathcal {O}(\tau ^2 M_t^k)\)  floating point operations (flops) since it involves inverting a \(\tau \times \tau \)  matrix.
The MSBL scheme, with \(s\)  iterations, has a complexity of \(\mathcal {O}(s\tau ^2 M^k)\)  flops [1]}.
The LCMMSE scheme has the lowest complexity of \(\mathcal {O}(M_t^k)\)  flops since it does not need any matrix inversion.
